1. Field of the Invention
The present invention relates to stable aqueous solution preparations containing azulene sodium sulfonate as an active ingredient, which are suited for use as a preventive or therapeutic medicine for inflammatory diseases in digestive organs, oral cavity and throat, otolaryngology, ophthalmology, etc., and which can be used easily and hygienically.
2. Discussion of the Background
Azulene sodium sulfonate is found in an extract of the plant camomile (Matricaria Chamomilla L.) which belongs to the Asteraceae originated in the South and East Europe. As a folk medicine, it has long been used to cure a variety of inflammatory diseases. Currently, it is widely used as an anti-inflammatory agent to be incorporated in medicines for treating gastritis and gastric ulcer, mouthwashes, oral preparations, eye drops and the like.
Azulene sodium sulfonate is generally formed into solids such as tablets, lozenges, granule, powder, and the like, with an exception of eye drops. Drugs for internal use are orally administered as they are, while mouthwashes are prepared by dissolving the solid drug in water just before dosing. This is primarily due to the fact that azulene sodium sulfonate is unstable and easily degraded in the aqueous solution as time passes and under diffused light.
Eye drops, which are the only preparation marketed in liquids, usually contain adjuvants such as thiosulfate (antioxidizing agent) and EDTA (chelating agent), and are provided in expensive air-tight containers. Some of the adjuvants cannot be used as ingredients of drugs for oral administration. Moreover, the stability of eye drop preparations is not sufficiently good.
Reflecting the increased number of patients suffering from oral diseases typified by stomatitis and sore throat, which may possibly be due to the overpopulation and environmental pollution, there has recently been a growing demand for OTC (over-the-counter) drugs which are easily applied to the oral cavity/throat and are free from adverse side effects. As a solution, lozenge or dissolving-on-use type preparations containing azulene sodium sulfonate are considered. However, they are not necessarily satisfactory in that the active ingredient, azulene sodium sulfonate, will not successfully reach the affected area via lozenge, while dissolving-on-use type will require water and a glass, which makes the whole process troublesome and non-hygienic.
Accordingly, there is still a demand for an aqueous solution preparation of azulene sodium sulfonate suited for the internal administration or the oral cavity/throat application. So far before the present invention, however, it has been considered difficult to industrially provide such an aqueous preparation containing azulene sodium sulfonate as an active ingredient, because the sulfonate is unstable in an aqueous solution, and hence, aqueous solution preparations of azulene sodium sulfonate have never existed.